Methylene chloride-free and optionally methanol-free paint stripper and /or gasket remover compositions

ABSTRACT

The present invention is directed to methylene chloride-free, and optionally methanol-free, paint stripper and gasket remover formulations as alternatives to methylene chloride-based paint strippers and gasket removers.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is directed to methylene chloride-free, andoptionally methanol-free, paint stripper and gasket removerformulations, as alternatives to methylene chloride-based paintstrippers and gasket removers.

[0003] 2. Brief Description of Related Technology

[0004] Methylene chloride has been the paint stripper and gasket removerof choice in industry for many years because it removes paints,coatings, and gaskets quickly, and works well on a variety ofsubstrates, including wood and metal. The largest use for methylenechloride in the United States is paint stripping and gasket removal withabout 40% of the 360 million pounds sold in the United States in 1994being for this application.¹ Paint stripping and gasket remover productsare widely used by maintenance workers at industrial complexes, aircraftpainters, furniture makers, and homeowners. Other major uses formethylene chloride include metal cleaning and finishing in electronicsmanufacturing, and as a process solvent in the pharmaceutical and filmcoatings industries. Despite the versatility of methylene chloride in avariety of applications, some industry experts believe that the use ofmethylene chloride in paint stripper and gasket remover products will becurtailed by government regulations due to concern over its toxicity inhumans. The U.S. Environmental Protection Agency currently classifiesmethylene chloride as a Group B2 probable human carcinogen of lowcarcinogenic hazard .²

[0005] Accordingly, it would be desirable to replace methylene chloridein such products with a chemical having comparable abilities, whilehaving a less extreme EPA classification.

[0006] Other halogenated solvents are known for use in paint strippingand/or gasket removing compositions. For instance, brominated solventsare known, such as n-propyl bromide. n-Propyl bromide is oftentimesrecommended as a paint stripper or gasket remover as a cold cleaningsolvent or in immersion applications. Another known halogenated solventis benzotrifluoride (also known as 1-chloro-4-(trifluoromethyl)benzene).See U.S. Pat. No. 5,756, 002.

[0007] A number of obstacles exist to the successful commercialdevelopment of a paint stripper and or gasket remover composition, evenone containing a halogenated solvent other than the one carbon variety,such as methylene chloride (or chloroform or carbon tetrachloride). Forinstance, while a large container of n-propyl bromide might be handy inindustrial, large scale operations where the parts to be stripped ofpaint or from which one or more gaskets to be removed are of significantsize, in many instances it is not convenient to perform a dippingoperation. Rather, many end users would prefer to be able to apply sucha composition directly on the part and remove the unwanted paint orgasket shortly thereafter. However, halogenated solvents, such asn-propyl bromide, themselves are very often low viscosity and thus tendto either run off the part or evaporate quickly after application. Thisresults in incomplete cleaning after one application or the necessity ofmany repeat applications, with much waste of material and time.

[0008] While thickeners may be used to enhance the viscosity of thehalogenated solvent, which will improve the run off problem, mostconventional thickeners, such as silicas, clays and the like, themselvesdo not have the proper film forming properties to allow the developmentof a wet film of the halogenated solvent. In addition, the addition of athickener will likely create a two part system, requiring agitatingmixing prior to application.

[0009] There therefore exists a need for formulations for stripping,removing and cleaning parts that are free of methylene chloride, andoptionally methanol as well, and provide comparable performanceabilities to formulations based on that halogenated solvent.

[0010] A methylene chloride-free, single phase, paint stripping andgasket removing composition, comprising a halogened hydrocarbon liquid,having more than one carbon atom; a polar oxygenated organic liquid; anda hydrogen bondable thickener, wherein the polar oxygenated organicliquid and hydrogen bondable thickener are present in sufficent amountsto render the composition in a single phase and to synergisticallyincrease the viscosity of the composition beyond the viscosity of acomposition, without either of the polar oxygenated organic liquid orthe hydrogen bondable thickener in substantially similar amounts.

SUMMARY OF THE INVENTION

[0011] This invention provides formulations for paint stripper andgasket remover products that are based on solvents other than methylenechloride or any other solvent classified as a possible human carcinogen,and are effective alternatives to methylene chloride-based formulationsfor paint stripping and gasket removal.

[0012] The inventive compositions may be applied to the surface of apart in a controlled manner, and because of the rhelogical properties ofthe composition, will remain on the part for a time sufficient to allowthe paint to be stripped or gasket to be removed to swell and thereafterbe stripped or removed from the surface of the part. The swelling of thepaint or gasket indicates that the composition has penetrated and/ordissolved to some degree the paint or gasket.

[0013] The alternative solvents used in this invention are halogenated.These solvents include brominated solvents such as n-propyl bromide(also known as 1-bromopropane), chlorinated solvents such as a mixtureof 1-chloro-2-methylbenzene and 1-chloro-4-methylbenzene (also known aschlorotoluenes), and chlorinated/fluorinated solvents such as1-chloro-4-(trifluoromethyl)benzene (also known asp-chlorobenzotrifluoride) and 1,2-dichloro-4-(trifluoromethyl)benzene(also known as dichlorobenzotrifluoride). This invention offers manyadvantages including that since none of the solvents employed in theformulations described herein are classified as potential humancarcinogens, these formulations are effective alternatives to methylenechloride-based formulations or other formulations containing humancarcinogens or possible human carcinogens for removing a range ofpaints, coatings, and gaskets quickly and efficiently.

[0014] In another aspect of the invention, compositions which includesuch alternative solvents are optionally also prepared with polaroxygenated organic compounds, other than methanol, to which manycountries are seeking to limit user exposure. In addition to such polaroxygenated organic compounds other than methanol are included alcohols(other than methanol), diols, polyols, ethers, ketones, esters and thelike.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 depicts chemical structures of alternative solvents used inpaint and gasket remover formulations within the present invention.

[0016]FIG. 2 depicts a comparison of n-propyl bromide formulation(Sample A) with formulations within the present invention as regardsspecimen weights, initial and final measurements (grams).

[0017]FIG. 3 depicts a comparison of1-chloro-2-methylbenzene/1-chloro-4-methylbenzene (mixture) formulation(Sample B) with typical alternative formulations with the presentinvention as regards specimen weights, initial and final measurements(grams).

[0018]FIG. 4 depicts a comparison of 1-chloro-4-(trifluoromethyl)benzeneformulation (Sample C) with typical alternative formulations with thepresent invention as regards specimen weights, initial and finalmeasurements (grams).

[0019]FIG. 5 depicts a comparison of1,2-dichloro-4-(trifluoromethyl)benzene formulation (Sample D) withtypical alternative formulations in accordance with the presentinvention as regards specimen weights, initial and final measurements(grams).

DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention provides a single phase, paint stripper andgasket remover composition, which is free of methylene chloride. Thecomposition in its broad form provides a halogenated hydrocarbon liquid,such as brominated or chlorinated hydrocarbon liquids, other thanchlorinated one carbon compounds; a polar oxygenated organic liquid; anda hydrogen bondable thickener. The polar oxygenated organic liquid andhydrogen bondable thickener are present in sufficent amounts to renderthe composition in a single phase and to synergistically increase theviscosity of the composition beyond the viscosity of a compositionwithout either of the polar oxygenated organic liquid or the hydrogenbondable thickener in substantially similar amounts.

[0021] The inventive compositions are based on halogenated hydrocarbonliquids, such as brominated or chlorinated hydrocarbon liquids, otherthan chlorinated one carbon compounds, such as methylene chloride,chloroform, or carbon tetrachloride, which are each classified by theU.S. EPA as a human carcinogen. These halogenated hydrocarbon liquidsinclude brominated solvents such as n-propyl bromide (also known as1-bromopropane), chlorinated solvents such as a mixture of1-chloro-2-methylbenzene and 1-chloro-4-methylbenzene³ (also known aschlorotoluenes), and chlorinated/fluorinated solvents such as1-chloro-4-(trifluoromethyl)-benzene⁴ (also known asp-chlorobenzotrifluoride) and 1,2-dichloro-4-(trifluoromethyl)-benzene⁵(also known as dichlorobenzotrifluoride). The chemical structures ofthese solvents are shown in FIG. 1.

[0022] The halogenated hydrocarbon liquid should be present in an amountwithin the range of about 40 to about 90, such as about 50 to about 80,desirably about 60 to about 75 percent by weight of the inventivecomposition.

[0023] Prior to this invention, commercially available methylenechloride-free paint stripper and gasket remover formulations were basedon alternative solvents that are generally not halogenated (e.g.,xylenes, toluene, acetone, butyrolactone, d-limonene, benzyl alcohol,N-methyl pyrrolidone, N,N-dimethylformamide, cyclohexanol, and the like)or that contain only small amounts of halogenated solvents. Oneadvantage of using the halogenated organic solvents rather than thenon-carcinogenic, non-halogenated hydrocarbon liquids described above isthat the former appear to be more effective at swelling and removing awide range of gasket materials. Brominated or chlorinated hydrocarbonliquids tend to be more aggressive than non-halogenated organic solventsbecause of a highly polarized carbon-halogen bond.

[0024] The polar oxygenated organic liquid may be selected from avariety of materials, including hydroxylated alkanols, hydroxylatedalkenols, hydroylated cycloalkanols, hydroxylated cycloalkenols, ethers,aldehydes, ketones, esters and combinations thereof. These materials arecapable of acting as hydrogen donors with a hydrogen acceptor. In theinventive compositions, the hydrogen acceptor may be the hydrogenbondable thickener. In these donor-acceptor pairs, while not intendingto be bound by theory, hydrogen bonding is believed to occur whichsynergistically improves the thickening ability of either componentalone in substantially similar amounts.

[0025] More specific examples of the hydroxylated alkanols include thealcohols, methanol, ethanol, propanols, butanols, pentanols, hexanols,heptanols, and the like, the glycols, ethylene glycols, propyleneglycols, butylene glycols, and the like, and the triol, glycerol. Ofcourse, combinations of these hydroxylated alkanols may be used as well.

[0026] More specific examples of the hydroxylated alkenols includepropenols, butenols, pentenols, hexenols, heptenols and combinationsthereof.

[0027] More specific examples of the hydroxylated cycloalkanols includecyclopentanols, cyclohexanols, cycloheptanols and combinations thereof.

[0028] More specific examples of the hydroxylated cycloalkenols includecyclopentenols, cyclohexenols, cycloheptenols and combinations thereof.

[0029] More specific examples of the ethers include dimethyl ether,diethyl ether, tetrahydrofuran and combinations thereof.

[0030] More specific examples of the aldehydes include acetaldehyde,propyl aldehyde, and combinations thereof.

[0031] More specific examples of the ketones include acetone,methylethyl ketone, cyclohexanone and combinations thereof.

[0032] More specific examples of the esters include ethyl formate, ethylacetate, methyl acetate, and combinations thereof.

[0033] The polar oxygenated organic liquid should be present in anamount within the range of about 0.01 to about 20, such as about 0.5 toabout 15, desirably about 1 to about 10 percent by weight of theinventive composition.

[0034] The hydrogen bondable thickener may be chosen from a host ofmaterials, such as alkylated celluloses, like methyl cellulose, hyroxypropyl methyl cellulose and combinations thereof. A commerciallyavailable example of these materials includes METHOCEL 311, from DowChemical. Another appropriate choice for the hydrogen bondable thickeneris alkylated silicas.

[0035] The hydrogen bondable thickener should be present in an amountwithin the range of about 0.01 to about 20, such as about 0.05 to about10, desirably about 0.2 to about 0.5 percent by weight of the inventivecomposition.

[0036] The compositions may also include a surfactant, particularlywhere the components would benefit from the surfactant to maintain asingle phase, and/or a paraffin wax, such as the commercially availablePARVAN 131.

[0037] The invention is also directed to a method of preparing theinventive compositions. The method includes the provision of therespective components and mixing them together for a sufficient amountof time to form a single phase composition.

[0038] The invention is further directed to a method of removing agasket or paint with the inventive compositions. The method includes theprovision of a gasketed or a painted part (which for the purposes ofthis application shall also include coatings, such as lacquer, varnish,enamel and the like), dispensing the inventive composition on and/orabout the gasketed or painted part, and allowing the inventivecomposition to swell the gasket and paint to permit facile removalthereof.

[0039] The invention is yet further directed to the inventivecomposition in an aerosol form, in which the composition furtherincludes a propellant. In this regard, the present invention alsocontemplates articles of manufacture which include a container forpackaging the inventive composition; the inventive composition disposedtherewithin together with a propellant. The propellant should be chosenso that it is soluble or otherwise compatible with the overallcomposition such that it can be dispensed in a single phase, therebyavoiding separation of the propellant from the other components in thecontainer during storage. Suitable propellants for use in the presentinvention include, without limitation, carbon dioxide, isobutane,dimethylether, l,1,1,2-tetrafluoroethane and combinations thereof. Whenpresent, the propellant should be used in amounts sufficient tofacilitate delivery of the composition from an aerosol container. Forexample, the propellant may be used in amounts of about 1 to about 50percent by weight, desirably in an amount of about 25 to about 35percent by weight of the inventive composition.

[0040] The present invention will be further illustrated by reference tothe following non-limiting examples.

EXAMPLES

[0041] The formulations set forth in Tables 1-4 are based on thesolvents shown in FIG. 1, and are examples of effective methylenechloride-free formulations for paint and gasket removers. Tables 5-8show commercially available gasket remover formulations based onmethylene chloride, xylenes and acetone, and N-methyl pyrrolidone, and aformulation based on cyclohexanol, respectively. TABLE 1 MethyleneChloride-Free Paint and Gasket Remover Formulation Based on n-PropylBromide as the Primary Solvent (Sample A) Weight Component Quantity(grams) Order of Addition* Percentage n-Propyl Bromide 121.3 1 87.3Methanol 12.1 2 8.7 Hydroxy Propyl 0.5 3 0.36 Methyl Cellulose PARVAN131 1.4 4 1 Mineral Spirits 2.8 5 2 Total 138.3 — ˜100

[0042] TABLE 2 Methylene Chloride-Free Paint and Gasket RemoverFormulation Based on a Mixture of 1-Chloro-2-Methylbenzene and1-Chloro-4-Methylbenzene as the Primary Solvents (Sample B) Order ofWeight Component Quantity (grams) Addition* Percentage Mixture of1-Chloro- 111.2 1 80.0 2-Methylbenzene and 1-Chloro-4- MethylbenzeneMethanol 11.1 2 8.0 Acetone 11.1 3 8.0 Hydroxy Propyl 0.5 4 0.36 MethylCellulose PARVAN 131 1.4 5 1 Mineral Spirits 2.8 6 2 Total 138.1 — ˜100

[0043] TABLE 3 Methylene Chloride-Free Paint and Gasket RemoverFormulation Based on 1-Chloro-4-(Trifluoromethyl)-benzene as the PrimarySolvent (Sample C) Weight Component Quantity (grams) Order of Addition*Percentage 1-Chloro-4- 108.4 1 76.4 (Trifluoromethyl)- benzene Methanol10.8 2 7.6 Acetone 10.8 3 7.6 Hydroxy Propyl 0.8 4 0.58 Methyl CellulosePARVAN 131 2.25 5 1.6 Mineral Spirits 4.5 6 3.3 Total 137.55 — ˜100

[0044] TABLE 4 Methylene Chloride-Free Paint and Gasket RemoverFormulation Based on 1,2-Dichloro-4-(Trifluoromethyl)-benzene as thePrimary Solvent (Sample D) Weight Component Quantity (grams) Order ofAddition* Percentage 1,2-Dichloro-4- 108.4 1 76.4 (Trifluoromethyl)-benzene Methanol 10.8 2 7.6 Acetone 10.8 3 7.6 Hydroxy Propyl 0.8 4 0.58Methyl Cellulose PARVAN 131 2.25 5 1.6 Mineral Spirits 4.5 6 3.3 Total137.55 — ˜100

[0045] TABLE 5 Commercially Available Methylene Chloride-Based Paint andGasket Remover Formulation (Sample E) Weight Component Quantity (grams)Order of Addition* Percentage Methylene Chloride 122.5 1 88.1 Methanol12.2 2 8.8 Proprietary 4.3 3 3.1 Ingredients^(*) Total 139 — 100

[0046] TABLE 6 Commercially Available Xylenes and Acetone-Based Paintand Gasket Remover Formulation (Sample F) Weight Component Quantity(grams) Order of Addition* Percentage Xylenes 62.7 1 45.1 Acetone 63.1 245.4 Methanol 6.8 3 4.9 Proprietary 6.4 4 4.6 Ingredients^(*) Total 139— 100

[0047] TABLE 7 Commercially Available N-Methyl Pyrrolidone-Based Paintand Gasket Remover Formulation (Sample G) Weight Component Quantity(grams) Order of Addition* Percentage N-Methyl 122.5 1 88.1 PyrrolidoneMethanol 12.2 2 8.8 Proprietary 4.3 3 3.1 Ingredients^(*) Total 139 —100

[0048] TABLE 8 Cyclohexanol-Based Paint and Gasket Remover Formulation(Sample H) Weight Component Quantity (grams) Order of Addition*Percentage Cyclohexanol 122.5 1 88.1 Methanol 12.2 2 8.8 Hydroxy Propyl0.38 3 0.27 Methyl Cellulose PARVAN 131 1.08 4 0.78 Mineral Spirits 2.155 1.55 Total 138.31 — ˜100

[0049] In Table 9-16, the formulations of Tables 1-8 are set forthagain, though in an aerosol form—that is, a propellant has been addedand the formulation packaged in an aerosol can. TABLE 9 MethyleneChloride-Free Paint and Gasket Remover Formulation in Aerosol Form Basedon n-Propyl Bromide as the Primary Solvent (Sample A) Weight ComponentQuantity (grams) Order of Addition* Percentage n-Propyl Bromide 138.7 161.1 Methanol 13.8 2 6.1 Hydroxy Propyl 0.57 3 0.25 Methyl CellulosePARVAN 131 1.6 4 0.7 Mineral Spirits 2.74 5 1.2 Propellant 68.1 6 30.0Total 225.5 — ˜100

[0050] TABLE 10 Methylene Chloride-Free Paint and Gasket RemoverFormulation in Aerosol Form Based on a Mixture of1-Chloro-2-Methylbenzene and 1-Chloro-4-Methylbenzene as the PrimarySolvents (Sample B) Order of Weight Component Quantity (grams) Addition*Percentage Mixture of 1-Chloro 127.1 1 56.0 2-Methylbenzene and1-Chloro-4- Methylbenzene Methanol 12.7 2 5.6 Acetone 12.7 3 5.6 HydroxyPropyl 0.57 4 0.25 Methyl Cellulose PARVAN 131 1.6 5 0.7 Mineral Spirits2.74 6 1.2 Propellant 68.1 7 30.0 Total 225.5 — ˜100

[0051] TABLE 11 Methylene Chloride-Free Paint and Gasket RemoverFormulation in Aerosol Form Based on1-Chloro-4-(Trifluoromethyl)-benzene as the Primary Solvent (Sample C)Order of Component Quantity (grams) Addition* Weight Percentage1-Chloro-4- 124.0 1 54.6 (Trifluoromethyl)- benzene Methanol 12.3 2 5.4Acetone 12.3 3 5.4 Hydroxy Propyl 0.91 4 0.4 Methyl Cellulose PARVAN 1312.58 5 1.14 Mineral Spirits 5.15 6 2.28 Propellant 68.1 5 30.0 Total225.34 — ˜100

[0052] TABLE 12 Methylene Chloride-Free Paint and Gasket RemoverFormulation in Aerosol Form Based on1,2-Chloro-4-(Trifluoromethyl)-benzene as the Primary Solvent (Sample D)Order of Component Quantity (grams) Addition* Weight Percentage1,2-Chloro-4- 124.0 1 54.6 (Trifluoromethyl)- benzene Methanol 12.3 25.4 Acetone 12.3 3 5.4 Hydroxy Propyl 0.91 4 0.4 Methyl Cellulose PARVAN131 2.58 5 1.14 Mineral Spirits 5.15 5 2.28 Propellant 68.1 5 30.0 Total225.34 — ˜100

[0053] TABLE 13 Commercially Available Methylene Chloride-Based Paintand Gasket Remover Formulation in Aerosol Form (Sample E) Order ofComponent Quantity (grams) Addition* Weight Percentage MethyleneChloride 140.0 1 61.7 Methanol 14.1 2 6.2 Proprietary 4.8 3 2.1Ingredients* Propellant 68.1 4 30 Total 227 — 100

[0054] TABLE 14 Commercially Available Xylenes and Acetone-Based Paintand Gasket Remover Formulation in Aerosol Form (Sample F) Order ofComponent Quantity (grams) Addition* Weight Percentage Xylenes 71.7 131.6 Acetone 72.2 2 31.8 Methanol 7.7 3 3.4 Proprietary 7.3 4 3.2Ingredients* Propellant 68.1 5 30 Total 227 — 100

[0055] TABLE 15 Commercially Available N-Methyl Pyrrolidone-Based Paintand Gasket Remover Formulation in Aerosol Form (Formulation Sample G)Quantity Order of Component (grams) Addition* Weight Percentage N-MethylPyrrolidone 140.0 1 61.7 Methanol 14.1 2 6.2 Proprietary 4.8 3 2.1Ingredients* Propellant 68.1 4 30 Total 227 — 100

[0056] TABLE 16 Cyclohexanol-Based Paint and Gasket Remover Formulationin Aerosol Form (Sample H) Order of Component Quantity (grams) Addition*Weight Percentage Cyclohexanol 140.0 1 61.7 Methanol 14.1 2 6.2 HydroxyPropyl 0.43 3 0.19 Methyl Cellulose PARVIN 131 1.2 4 0.53 MineralSpirits 2.4 5 1.06 Propellant 68.1 6 30 Total 226.2 — 100

[0057] In Tables 17-23, in addition to replacing methylene chloride withn-propyl bromide, n-propyl bromide was used together with hydroxy propylmethyl cellulose as a first control (Sample I), and with hydroxy propylmethyl cellulose and methanol as a second control (Sample J) incomparison with replacement alcohols, as set forth in Samples K-O. Inaddition to alcohols, diols, such as ethylene glycol, propylene glycols(i.e., 1,1- and 1,2-propylene glycol) and the like, polyols, such asglycerol and the like, ethers, such as dimethyl ether, diethyl ether andthe like, aldehydes, such as acetaldehyde, ketones, such as acetone,methylethyl ketone and the like, and esters may be used. Broadlyspeaking, any organic liquid capable of forming a hydrogendonor-hydrogen acceptor pair with another component of the compositionmay be used, provided that it maintains a shelf stable, single phasecomposition.

[0058] These formulations were used to determine the relative thickeningpower of the combination of methyl cellulose and the alcohols. Thethickening ability allows the formulation, once applied to a gasket forinstance, to remain in place so that the formulation may swell thegasket, thereby allowing for removal from the part on which the gaskethas been applied. TABLE 17 n-Propyl Bromide/Methyl Cellulose Formulation(Sample I) Viscosity Component Quantity (grams) Weight Percentage (cps)n-Propyl Bromide 61.45 99.6 <3 Hydroxy Propyl 0.263 0.4 Methyl CelluloseTotal 61.713 100

[0059] A comparable formulation prepared with n-propyl bromide andmethanol demonstrated a comparable viscosity. TABLE 18 n-PropylBromide/Methanol/Methyl Cellulose Formulation (Sample J) ViscosityComponent Quantity (grams) Weight Percentage (cps) n-Propyl Bromide61.45 88.7 14.5 Methanol 6.15 8.9 Hydroxy Propyl 0.263 0.4 MethylCellulose Mineral Spirits 1.40 2.0 Total 69.263 100

[0060] TABLE 19 n-Propyl Bromide/Ethanol/Methyl Cellulose Formulation(Sample K) Viscosity Component Quantity (grams) Weight Percentage (cps)n-Propyl Bromide 61.45 88.7 13.5 Ethanol 6.15 8.9 Hydroxy Propyl 0.2630.4 Methyl Cellulose Mineral Spirits 1.40 2.0 Total 69.263 100

[0061] TABLE 20 n-Propyl Bromide/n-Propanol/Methyl Cellulose Formulation(Sample L) Viscosity Component Quantity (grams) Weight Percentage (cps)n-Propyl Bromide 61.45 88.7 11.2 n-Propanol 6.15 8.9 Hydroxy Propyl0.263 0.4 Methyl Cellulose Mineral Spirits 1.40 2.0 Total 69.263 100

[0062] TABLE 21 n-Propyl Bromide/I-Propanol/Methyl Cellulose Formulation(Sample M) Viscosity Component Quantity (grams) Weight Percentage (cps)n-Propyl Bromide 61.45 88.7 i-Propanol 6.15 8.9 Hydroxy Propyl 0.263 0.46.9 Methyl Cellulose Mineral Spirits 1.4 2.0 Total 69.263 100

[0063] TABLE 22 n-Propyl Bromide/n-Butanol/Methyl Cellulose Formulation(Sample N) Viscosity Component Quantity (grams) Weight Percentage (cps)n-Propyl Bromide 61.45 88.7 n-Butanol 6.15 8.9 Hydroxy Propyl 0.263 0.46.7 Methyl Cellulose Mineral Spirits 1.4 2.0 Total 69.263 100

[0064] TABLE 23 n-Propyl Bromide/Cyclohexanol/Methyl CelluloseFormulation (Sample O) Viscosity Component Quantity (grams) WeightPercentage (cps) n-Propyl Bromide 61.45 88.7 Cyclohexanol 6.15 8.9Hydroxy Propyl 0.263 0.4 4.4 Methyl Cellulose Mineral Spirits 0.263 2.0Total 69.263 100

Evaluation of Formulations as Regards Swellability

[0065] The formulations set forth in Tables 1-8 and 17-23 were evaluatedin accordance with ASTM D 543-95, Standard Practices for Evaluating theResistance of Plastics to Chemical Reagents. In this test method, thespecimens are first measured for dimensions and weight.⁶ The specimensare then immersed in each formulation for a period of time of about 10minutes at room temperature, removed from the formulation and dried witha paper wipe, and measured again for weight and dimensional changes. Thetypes of specimens evaluated are shown in Table 24. TABLE 24 Types ofSpecimens Used to Evaluate New Gasket Remover Formulations Types ofSamples Buna-N Natural Rubber Cork Neoprene EPDM Plain Back Cork FiberSilicone Gore-Tex PTFE Viton

[0066] An indicator of performance in this test is sample swelling,since commercially available paint and gasket remover products removemost types of gaskets fairly quickly by significantly swelling the paintor gasket. Table 25 and FIGS. 2-5 show the average gain in weightexhibited by each type of sample which is a function of sample swelling.These data indicate that the best formulations for swelling a wide rangeof gasket materials generally contain halogenated organic solvents astheir primary constituent (e.g., methylene chloride, n-propyl bromide,1-chloro-2-methylbenzene/1-methyl-4-methylbenzene (mixture),1-chloro-4-(trifluoromethyl)benzene, and1,2-dichloro-4-(trifluoromethyl)benzene). TABLE 25 Changes in Weight forSamples Immersed in Formulations Containing Various Primary SolventComponents Changes in Weight (Average Initial Weight in Grams/ AverageFinal Weight in Grams/ Average Percent Increase in Weight) for SamplesImmersed in Formulations Containing the Following Primary SolventComponents Sample E, Sample E, Sample E, Sample A, Sample A, Sample A,Methylene Methylene Methylene n-Propyl n-Propyl n-Propyl Chloride,Chloride, Chloride, Bromide, Bromide, Bromide, Average Average AverageAverage Average Average Initial Final Increase in Initial Final Increasein Sample Weight (g) Weight (g) Weight (%) Weight (g) Weight (g) Weight(%) Buna-N 1.11 2.57 132 1.15 2.02 76 Neoprene 1.23 1.49 21 1.23 1.55 26Cork 0.64 1,49 133 0.62 1.30 110 EPDM 1.07 1.20 12 1.02 1.26 24 Fiber0.78 0.95 22 0.75 0.86 15 Gore-Tex PTFE 0.63 1.10 75 0.67 1.20 79Natural Rubber 2.23 2.73 22 2.31 2.73 18 Plain Back Cork 0.24 0.63 1630.24 0.40 67 Silicone 1.30 1.85 42 1.35 2.15 59 Viton 2.07 2.12 2 2.092.12 1 Sample B, Sample B, Sample C, 1-Chloro-2- 1-Chloro-2- 1-Chloro-2-Methylbenzene Methylbenzene Methylbenzene Sample C, Sample C, and andand 1-Chloro-4- 1-Chloro-4- 1-Chloro-4- 1-Chloro-4- 1-Chloro-4-1-Chloro-4- (Trifluoro- (Trifluoro- (Trifluoro- MethylbenzeneMethylbenzene Methylbenzene methyl)- methyl)- methyl)- (Mixture),(Mixture), (Mixture), benzene, benzene, benzene, Average Average AverageAverage Average Average Initial Final Increase in Initial Final IncreaseSample Weight (g) Weight (g) Weight (g) Weight (g) Weight (g) in WeightBuna-N 1.06 1.65 56 1.14 1.66 46 Necoprene 1.25 1.54 23 1.24 1.35 9 Cork0.59 1.12 90 0.63 1.08 71 EPDM 1.03 1.32 28 1.07 1.19 11 Fiber 0.77 0.9523 0.75 0.89 19 Gore-Tex PTFE 0.65 0.89 37 0.66 1.43 117 Natural Rubber2.23 2.57 15 2.13 2.33 9 Plain Back Cork 0.24 0.48 100 0.23 0.39 70Silicone 1.37 1.81 32 1.39 1.89 36 Viton 2.03 2,03 0 1.99 2.02 2 SampleD, 3,4- Sample D, Dichloro-4- Sample D, 3,4- Trifluoro- Sample F, SampleF, Sample F, 3,4-Dichloro-4- Dichloro-4- methyl)- Xylenes and Xylenesand Xylenes and (Trifluoro- (Trifluoro- benzene, Acetone Acetone Acetonemethyl)- methyl)- Average (Mixture), (Mixture), (Mixture), benzene,benzene, Increase Average Average Average Average Initial Average Finalin Weight Initial Final Increase in Sample Weight (g) Weight (g) (%)Weight (g) Weight (g) Weight (%) Buna-N 1.16 1.57 35 1.12 1.64 46Neoprene 1.25 1.35 8 1.25 1.35 8 Cork 0.63 1.00 59 0.60 0.91 52 EPDM1.02 1.13 11 1.03 1.07 4 Fiber 0.76 0.92 21 0.79 0.86 9 Gore-Tex PTFE0.66 1.47 123 0.65 0.84 29 Natural Rubber 2.17 2.37 9 2.18 2.31 6 PlainBack Cork 0.23 0.40 74 0.23 0.31 35 Silicone 1.38 1.70 23 1.38 1.62 17Viton 2.03 2.05 1 2.01 2.34 16 Sample G, Sample G, Sample G, N-MethylN-Methyl N-Methyl Sample H, Sample H, Sample H, Pyrrolidone,Pyrrolidone, Pyrrolidone, Cyclohexanol, Cyclohexanol, Cyclohexanol,Average Average Average in Average Average Average Initial FinalIncrease Initial Final Increase in Sample Weight (g) Weight (g) Weight(%) Weight (g) Weight (g) Weight (%) Buna-N 1.08 1.41 31 1.11 1.12 1Neoprene 1.24 1.27 2 1.25 1.25 0 Cork 0.62 0.85 37 0.65 0.72 11 EPDM1.02 1.02 0 1.04 1.04 0 Fiber 0.80 0.87 9 0.77 0.81 5 Gore-Tex PTFE 0.650.66 2 0.66 0.67 2 Natural Rubber 2.25 2.31 3 2.19 2.19 0 Plain BackCork 0.23 0.25 25 0.23 0.27 17 Silicone 1.36 1.38 1 1.36 1.37 1 Viton1.91 2.08 9 1.95 1.95 0

[0067] In Table 26, the weight uptake of Buta-N samples was determinedby the method described above in connection with formulations preparedalong the lines of Samples I-O, save for the methyl cellulose component.TABLE 26 Changes in Weight for Buta-N Samples Immersed in FormulationsContaining n-Propyl Bromide and Various Alcohols Average Initial AverageFinal Average Increase Sample Weight (g) Weight (g) in Weight (%) I1.329 1.986 49 J 1.286 1.850 44 K 1.288 1.845 43.2 L 1.313 1.841 40.2 M1.267 1.783 40.7 N 1.327 1.851 39.5 O 1.262 1.772 40.4

[0068] The following conclusions were drawn from these data:

[0069] Comparison of n-Propyl Bromide Formulation (Sample A) withMethylene Chloride Formulation (Sample E)

[0070] The n-propyl bromide formulation performs better than themethylene chloride formulation for swelling neoprene, EPDM, Gore-TexPTFE, and silicone substrates.

[0071] The n-propyl bromide formulation performs about as well as themethylene chloride formulation for swelling Viton substrates, butneither of these formulations swells Viton substrates significantly.

[0072] Although the methylene chloride formulation performs better thanthe n-propyl bromide formulation for swelling Buna-N, cork, fiber, plainback cork, and natural rubber substrates, the n-propyl bromideformulation swells these substrates sufficiently to be effective in thisapplication.

[0073] Comparison of n-Propyl Bromide Formulation (Sample A) withFormulations Based on Xylenes/Acetone (Sample F), N-Methyl Pyrrolidone(Sample G), and Cyclohexanol (Sample H)

[0074] The n-propyl bromide formulation performs better than the otherthree formulations for swelling Buna-N, neoprene, cork, EPDM, fiber,Gore-Tex PTFE, natural rubber, plain back cork, and silicone substrates.

[0075] The xylenes/acetone and N-methyl pyrrolidone formulations performbetter at swelling Viton substrates than the n-propyl bromideformulation. Neither the n-propyl bromide formulation nor thecyclohexanol formulation swells Viton substrates significantly.

[0076] Comparison of 1-Chloro-2-Methylbenzene/1-Chloro-4-Methylbenzene(Mixture) Formulation (Sample B) with Methylene Chloride Formulation(Sample E)

[0077] The 1-chloro-2-methylbenzene/1-chloro-4-methylbenzene formulationperforms better than the methylene chloride formulation for swellingneoprene and EPDM substrates, and performs about as well at swelling thefiber substrate.

[0078] Although the methylene chloride formulation performs better thanthe 1-chloro-2-methylbenzene/1-chloro-4-methylbenzene formulation forswelling Buna-N, cork, Gore-Tex PTFE, natural rubber, plain back cork,and silicone substrates, the latter formulation swells these substratessufficiently to be effective in this application. Neither of theseformulations swells Viton substrates significantly.

[0079] Comparison of 1-Chloro-2-Methylbenzene/1-Chloro-4-Methylbenzene(Mixture) Formulation (Sample B) with Formulations Based onXylenes/Acetone (Sample F), N-Methyl Pyrrolidone (Sample G), andCyclohexanol (Sample H)

[0080] The 1-chloro-2-methylbenzene/1-chloro-4-methylbenzene formulationperforms better than the other three formulations for swelling Buna-N,neoprene, cork, EPDM, fiber, Gore-Tex PTFE, natural rubber, plain backcork, and silicone substrates.

[0081] The xylenes/acetone and N-methyl pyrrolidone formulations performbetter than the 1-chloro-2-methylbenzene/1-chloro-4-methylbenzeneformulation at swelling Viton substrates. Neither the1-chloro-2-methylbenzene/1-chloro-4-methylbenzene formulation nor thecyclohexanol formulation swells Viton substrates significantly.

[0082] Comparison of 1-Chloro-4-(Trifluoromethyl)benzene Formulation(Sample C) with Methylene Chloride Formulation (Sample E)

[0083] The 1-chloro-4-(trifluoromethyl)-benzene formulation performsbetter than-the methylene chloride formulation for swelling Gore-TexPTFE substrates, and performs about as well for swelling EPDM, fiber,and Viton substrates. Neither of these formulations swells Vitonsubstrates significantly.

[0084] Although the methylene chloride formulation performs better thanthe 1-chloro-4-(trifluoromethyl)-benzene formulation for swellingBuna-N, neoprene, cork, natural rubber, plain back cork, and siliconesubstrates, the latter formulation swells Buna-N, cork, plain back cork,and silicone substrates sufficiently to be effective in thisapplication.

[0085] The 1-chloro-4-(trifluoromethyl)-benzene formulation does notswell neoprene or natural rubber substrates significantly.

[0086] Comparison of 1-Chloro-4-(Trifluoromethyl)-benzene Formulation(Sample C) with Formulations Based on Xylenes/Acetone (Sample F),N-Methyl Pyrrolidone (Sample G), and Cyclohexanol (Sample H)

[0087] The 1-chloro-4-(trifluoromethyl)benzene formulation performsbetter than the other three formulations for swelling cork, EPDM, fiber,Gore-Tex PTFE, natural rubber, plain back cork, and silicone substrates.

[0088] The 1-chloro-4-(trifluoromethyl)benzene formulation performsbetter than the N-methyl pyrrolidone and cyclohexanol formulations forswelling Buna-N, neoprene, and natural rubber substrates, and performsabout as well as the xylenes/acetone formulation for swelling Buna-N andneoprene substrates.

[0089] The xylenes/acetone and N-methyl pyrrolidone formulations performbetter than the 1-chloro-4-(trifluoromethyl)-benzene formulation forswelling Viton substrates. Neither the1-chloro-4-(trifluoromethyl)-benzene formulation nor the cyclohexanolformulation swells Viton substrates significantly.

[0090] Comparison of 1,2-Dichloro-4-(Trifluoromethyl)-benzeneFormulation (Sample D) with Methylene Chloride Formulation (Sample E)

[0091] The 1,2-dichloro-4-(trifluoromethyl)benzene formulation performsbetter than the methylene chloride formulation for swelling Gore-TexPTFE substrates, and performs about as well for swelling EPDM, fiber,and Viton substrates. Neither formulation is very effective at swellingViton substrates.

[0092] Although the methylene chloride formulation performed better thanthe 1,2-dichloro-4-(trifluoromethyl)-benzene formulation for swellingBuna-N, neoprene, cork, natural rubber, plain back cork, and siliconesubstrates, the latter formulation swelled Buna-N, cork, plain backcork, and silicone substrates sufficiently to be effective in thisapplication.

[0093] The 1,2-dichloro-4-(trifluoromethyl)-benzene formulation does notswell neoprene or natural rubber significantly.

[0094] Comparison of 1,2-Dichloro-4-(Trifluoromethyl)-benzeneFormulation (Sample D) and Formulations Based on Xylenes/Acetone (SampleF), N-Methyl Pyrrolidone (Sample G), and Cyclohexanol (Sample H)

[0095] The 1,2-dichloro-4-(trifluoromethyl)-benzene formulation performsbetter than the other three formulations for swelling cork, EPDM, fiber,Gore-Tex PTFE, natural rubber, plain back cork, and silicone substrates.

[0096] The xylenes/acetone formulation performs better than the1,2-dichloro-4-(trifluoromethyl)-benzene formulation at swelling Buna-Nand Viton substrates, and performs about as well as the latterformulation at swelling neoprene substrates.

[0097] The 1,2-dichloro-4-(trifluoromethyl)-benzene formulation performsbetter than the N-methyl pyrrolidone and cyclohexanol formulations atswelling buna-N, neoprene, cork, EPDM, fiber, Gore-Tex PTFE, naturalrubber, plain back cork, and silicone substrates.

[0098] The N-methyl pyrrolidone formulation performs better than the1,2-dichloro-4-(trifluoromethyl)-benzene formulation at swelling Vitonsubstrates. Neither the 1,2-dichloro-4-(trifluoromethyl)benzeneformulation nor the cyclohexanol formulation swells Viton substratessignificantly.

[0099] Methylene Chloride-Free, Non-Methanol Formulations

[0100] The ethanol-containing formulation unexpectedly remained in asingle phase solution and in a film longer than methanol-containingformulations, upon visual inspection.

[0101] This invention replaces methylene chloride in paint and gasketremover products with one of several halogenated organic solvents orsolvent combinations that are effective alternatives to methylenechloride-based formulations for the stripping of paints, and removal ofgaskets. Although because of its terrific solvency characteristics,methylene chloride is difficult to replace in these formulations, thesolvents used herein is have been shown to be effective in swelling arange of gasket material substrates when used as the primary solvent inthese formulations.

[0102] In addition, in another aspect, this invention uses a polaroxygenated organic liquid, desirably one other than methanol, incombination with a hydrogen bondable thickener to synergisticallyimprove the thickening of the formulation. This synergistic improvementin thickness provides for a longer on-part time because of the reducedopportunity for formulation run-off, and as such allows for a greateropportunity for swelling of the material, such as a gasket or paintcoating, to be removed.

[0103] This invention extends to the aerosol form of these formulationsusing a suitable propellant such as carbon dioxide, dimethyl ether,HFC-134a (1,1,1,2-tetrafluoroethane), hydrocarbon propellants (e.g.,mixtures of butane, isobutane, and/or propane) or other suitablepropellant.

[0104] The formulations described herein were compared to commerciallyavailable formulations based on methylene chloride, xylenes and acetone(mixture), and N-methyl pyrrolidone, and one experimental formulationbased on cyclohexanol in terms of their ability to swell a number ofdifferent types of gasket material substrates. These comparisons haveshown that none of these formulations consistently outperforms all ofthe others on all substrates, but some general trends were observed:

[0105] 1. The inventive formulations outperformed the methylenechloride-based formulation in terms of swelling a number of substrates,and performed sufficiently well on the remaining substrates to beeffective in this application. Regarding the latter substrates,differences in performance between the methylene chloride formulationand the formulations described herein should be subtle to the casualobserver using these products.

[0106] 2. The inventive formulations generally outperformed othercommercially available formulations based on typical, nonhalogenatedorganic solvents such as xylenes/acetone (mixture), and N-methylpyrrolidone, and one formulation based on cyclohexanol.

[0107] 3. Although the inventive formulations are effective at swellinga range of gasket material substrates, they appear to show the followinggeneral trend for effectiveness at swelling the range of substratestested: n-propyl bromide formulation (SampleA) >1-chloro-2-methylbenzene/1-chloro-4-methylbenzene (mixture)formulation (Sample B) >1-chloro-4-(trifluoromethyl)benzene formulation(Sample 1,2-dichloro-4-(trifluoromethyl)benzene formulation (Sample D).

[0108] Since none of the solvents employed in the formulations describedherein are classified by the EPA as possible human carcinogens, theseformulations are effective alternatives to methylene chloride-basedformulations or other formulations containing possible human carcinogensfor removing a range of paints, coatings, and gaskets quickly andefficiently.

[0109] The full scope of the invention is measured by the claims.

What is claimed is:
 1. A methylene chloride-free, single phase, paintstripping and gasket removing composition, comprising: a. a halogenedhydrocarbon liquid, having more than one carbon atom; b. a polaroxygenated organic liquid; and c. a hydrogen bondable thickener, whereinthe polar oxygenated organic liquid and hydrogen bondable thickener arepresent in sufficent amounts to render the composition in a single phaseand to synergistically increase the viscosity of the composition beyondthe viscosity of a composition, without either of the polar oxygenatedorganic liquid or the hydrogen bondable thickener in substantiallysimilar amounts.
 2. The composition according to claim 1, wherein thehalogenated hydrocarbon liquid is a member selected from the groupconsisting of n-propyl bromide, 1-chloro-2-methylbenzene,1-chloro-4-methylbenzene, 1-chloro-4-(trifluoromethyl)-benzene,1,2-dichloro-4-(trifluoromethyl)-benzene, and combinations thereof. 3.The composition according to claim 1, wherein the halogenatedhydrocarbon liquid is n-propyl bromide.
 4. The composition according toclaim 1, wherein the halogenated hydrocarbon liquid is present in anamount within the range of about 40 to about 90 percent by weight. 5.The composition according to claim 1, wherein the halogenatedhydrocarbon liquid is present in an amount within the range of aboutdesirably 60 to about 75 percent by weight.
 6. The composition accordingto claim 1, wherein the polar oxygenated organic liquid is a memberselected from the group consisting of hydroxylated alkanols,hydroxylated alkenols, hydroylated cycloalkanols, hydroxylatedcycloalkenols, ethers, ketones, esters and combinations thereof.
 7. Thecomposition according to claim 1, wherein the polar oxygenated organicliquid is a hydroxylated alkanol selected from the group consisting ofmethanol, ethanol, propanols, butanols, pentanols, hexanols, heptanols,ethylene glycols, propylene glycols, butylene glycols, glycerol, andcombinations thereof.
 8. The composition according to claim 1, whereinthe polar oxygenated organic liquid is a hydroxylated alkenol selectedfrom the group consisting of propenols, butenols, pentenols, hexenols,heptenols and combinations thereof.
 9. The composition according toclaim 1, wherein the polar oxygenated organic liquid is a hydroxylatedcycloalkanol selected from the group consisting of cyclopentanols,cyclohexanols, cycloheptanols and combinations thereof.
 10. Thecomposition according to claim 1, wherein the polar oxygenated organicliquid is a hydroxylated cycloalkenol selected from the group consistingof cyclopentenols, cyclohexenols, cycloheptenols and combinationsthereof.
 11. The composition according to claim 1, wherein the polaroxygenated organic liquid is an ether selected from the group consistingof dimethyl ether, diethyl ether, and combinations thereof.
 12. Thecomposition according to claim 1, wherein the polar oxygenated organicliquid is a ketone selected from the group consisting of acetone, methylethyl ketone, and combinations thereof.
 13. The composition according toclaim 1, wherein the polar oxygenated organic liquid is an esterselected from the group consisting of elkyl formate, methyl acetate,ethyl acetate, and combinations thereof.
 14. The composition accordingto claim 1, wherein the polar oxygenated organic liquid is present in anamount within the range of about 0.1 to about 20 weight percent.
 15. Thecomposition according to claim 1, wherein the polar oxygenated organicliquid is present in an amount within the range of about 1 to about 10percent by weight.
 16. The composition according to claim 1, wherein thehydrogen bondable thickener is a member selected from the groupconsisting of alkylated celluloses, alkylated silicas and combinationsthereof.
 17. The composition according to claim 1, wherein the hydrogenbondable thickener is hydroxyl propyl methyl cellulose.
 18. Thecomposition according to claim 1, wherein the hydrogen bondablethickener is present in an amount within the range of about 0.01 toabout 20 percent by weight.
 19. The composition according to claim 1,further comprising a parrafin wax.
 20. The composition according toclaim 1, further comprising a surfactant.
 21. A methylene chloride-free,single phase, paint stripping and gasket removing composition,comprising: a. n-propyl bromide, in an amount within the range of fromabout 40 to about 90 percent by weight; b. a polar oxygenated organicliquid selected from the group consisting of methanol, ethanol, andcombinations thereof, in an amount within the range of from about 0.01to about 20 percent by weight; and c. a hydrogen bondable thickener,wherein the hydrogen bondable thickener is an alkylated cellulose, in anamount within the range of from about 0.01 to about 20 percent byweight.
 22. A method of preparing a composition according to any one ofclaims 1 or 21, providing components (a) to (c) in a suitable amount andmixing for a time sufficient to form a single-phase paint stripper andgasket remover composition.
 23. A method of stripping paint or a gasketwith a composition according to any one of claims 1 or 21, comprisingthe steps of: a. dispensing the composition onto a paint- orgasket-covered part; b. allowing the composition to remain in contactwith the covered part for a time sufficient to allow the paint or gasketto swell; and c. removing at least a portion of the swelled paint orgasket from the part.
 24. The composition according to any one of claim1 or 21, in an aerosol form, further comprising a propellant.